Refers to a relationship
between members of different species
from which they both derive
some form of advantage. The nature of the benefit for each species may be quite different, e.g. one partner
might gain protection from predators where as one gains a nesting
site or food source.
A good example of this is the relationship between humans and dogs, especially in prehistoric times. Both species gained a lot from this relationship and it is one we continue to cultivate to the present day.